Fused bifocal lens.



E. J. FINK.

FUSED BIFOCAL LENS.

APPLICATION r1120 11111.21. 1911.

Patented Feb. 15, 1916.

2 SHEETS-SH EET I1 I QHo-mmgfl E. J. FINK.

FUSED' BIFOCAL LENS.

APPLICATION FILED IAII.2I.' I91].

1,171,419.. 7 Patented Feb; 15,1916.

2 SHEETSS'HEET 2.

EDWARD J. FINK, 0F SYCMEORE, ILLINOIS.

FUSES!) BIFOCAL LENS.

Specification of Letters Patent.

Patented iFe Elli, 1916.

Application filed January 21, 1911. Serial No. 603,893.

To all whom it may concern:

Be it known that I, EDWARD J. FINK, a

citizen of the United States, residing at Sycamore, in the county ofDekalb and State 1. ll Improvements in Fused Bifocal of which thefollowing is a specitron.

N invention relates to bifocal lenses, and 'or its object to provide alens of this in which the separate parts are securdd her moreeffectively than has hitherto a possible. Bifocal lenses have hereto eshaving the distance and reading'lens ortions or fields properly arrangedthere by fusing together portions of glass of crent refractive power; orby separately king the lenses which are to form. the unplete bifocallens and securing the minor reading lens or scale between lens portionswhich together constitute the major or di tance lens, the various lensesbeing each man the proper curvature to produce the desired opticalresult,- It is to this latter class of bifocal lens that my inventionparticularly relates, and the main feature there of consists in fusingtogether the edges of the portions of the major lens with the minor lensinclosed between them.

Referrin to the drawings z Figure 1 shows plan and edge views of oneform of the device; Fig. 2 shows plan and edge views of a modified form;Fig. 3 shows plan and edge views of still another modification anddetail views of several forms of minor lens; Fig. 4 shows one form. ofattachment for securing the lenses to the nose bridge; Fig. 5 is adetail of such attachment; Fig. 6 shows a modified formof mounting; Fig.7 is a part plan, part section of the construction shown in Fig. 6;Figs. 8 and 9 show modified forms which may be given to the lens; andFigs. 10 and 11 show a further modification.

Referring to Fig. 1, it will be noted that the major lens is made in twohalves, in one or both of which is ground a suitable cavity to receivethe minor lens 0. This minor lens has, for the "sake of clearness ofdescription been shown in full lines, though obviously, no such lines ofdemarcation would actually appear in the lens. A A show these halvesseparated, theportion A? having a suitable cavityto receive apianolinois, have invented certain new and e been made either by sogrinding the nlr as to provide an integral piece of Joined. A A indicatehalf-portions of convex lens. In this instance each portion has one fiatjunction face and has its edges beveled. After the minor lens has beenplaced in its cavity, the portions A A may be temporarily securedtogether, and are then placed in a furnace or mufille and graduallyheated to a temperature just sufficiently high to fuse, and thus unite,the thin edges of the portions A, A thus producing what is in effect anintegral bifocal lens,

' as shown at A The thin beveled edges will readily fuse together beforethe heat has an opportunity to 'afl'ect the body of the lens. Thecementing of the lenses is thus entirely obviated, and the lens portionsare integrally lenses, each having a cavity so that a double convexminor lens can be secured between them, the completed bifocal lens beingshown at A. In the constructions shown in Fig. 1, the joining surfacesare flat, but as will be apparent from Fig. 2, the joining sur-' facesmay be curved. 3 B Show the separated portions each having a cavitytherein, and B shows the completed lens with the double convex. minorlens inclosed between the portions B B B B, B show a similanconstructionas applied to a double convex minor lens'in which one face has a greatercurvature than the other.

As shown in Fig; 3, the lens portions may be formed with projectionsa-a, 6-6, and the projections having their edges beveled. C C and C showthe separated portions and completed lens. 111. this figure are alsoshown several forms which may be given to the minor lens,() beingpiano-convex, concavo-convex, and 0 double convex in shape. Asshown inFigs. 3 and 4, each bifocal lens may haveat one end a projection such asa, which serves as a means for attachment of a yoke E, these yoltesbeing held in place by screws E the yokes having lugs E to which the bowD or nose bridge D (shown in dotted lines), is secured by screws E InFigs. 6 and 7 are shown fused edged bifocal lenses secured in frames ofa metal, such as aluminum. The frame is cast about the lens by placingthe lens in a" suitable mold and pouring the metal into the mold. Thismethod enables lugs P, Q to be formed on the frame, to which the bow For nose bridge F and other portions of a spectacle 110 or 'eyeass framemay be secured, as by screws In Fig. 8 is shown a lens having lugs ll, Hat. each end, and additional lugs li, K, these latter lugs serving asadditional means for holding the lens in place in the cast metal frame.The. logs H, H are shaped to have a fillet or groove between their endsand the body of the lens.

In Fig. 9 is shown a lens llarin still other form I, l of lug forattaching the bow or nose bridge, these rounded lugs I, I having agroove of dillerent shape from that shown in Fig. By means of these lugsor projections the nose holding device, such as spectacle bow oreye-glass clamp, can be attached without the necessity of drilling thelens, which necessarily weakens the lens and often causes breakagethereof. T he lugs or projections at the ends and sides of the lens mayobviously be made of a great Variety o'f shapes. It will of course beunderstood that the major and minor lenses will. be made of suchmaterial and such curvature as will produce the proper refractiveelfect.

In Figs. 10 and 11 is shown a further modification, in which the minorlens has its lower edge beve ed and in line with the lower edges of thetwo major lens portions. In this arrangement, the lower edge of theminor lens will be fused to and with the lower edges of the majorlenses. In this form as in those heretofore described, the

heat to which the lenses are subjected is only that heat sullicient tofuse together the thin beveled edges of the lenses, which can beeffected without danger of distortion of the major lens or the inclosedminor lens.

I claim:

1. A. bifocal lens consisting of a twmpar. major lens, and a minor lensinclosed within the major lens, the edges only of the parts of the majorlens being fused together.

A bifocal lens consisting of two major lens portions each having outercurved surfaces and inner-joining surfaces, and a minor located in adavity between the major mums l. A lens consisting of two lens portionshaving their beveled edges only lused together.

5. A bi t'ocal lens consisting of a two-part major lens and a minor lensbetween them, the lower edge only of the minor lens being; united byfusion to a lower edge only of a major lens. 1

6. A lens, consisting of two lens portions, the edges only of such lensportions being fused together.

7. A. bifocal lens, consisting of a. twopart major lens and a mine: lensbetwee them, said major lenses united by edge fusion only, the loweredge only of the minor lens being fused with the lower edges only of themajor lenses.

8. The method of forming a lens, which comprises a two-part major lensand a minor 'lcns inclosed within the major lens, which consists insubjecting the above-inciu'zionod parts assembled together to a heatsutlicient to fuse together the edges only of the major lens.

9. The process of forming a bifocal lens consisting of two bevel-edgedmajor lens pmitions having inclosed between them, a minor lens, whichconsists in subjecting the assembled parts to a heat suliicient to fusethe beveled edge portions only.

In testimony whereof, I allix my signature in presence of two witnesses.

EDWAPD J. FINE. Nitmsses:

F. Annnn, L. (l. Wsnrmi.

